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November 19, 2009 AT 10:29 pm

PCB routing with EAGLE (video)


PCB routing with EAGLE – a one hour session, all in 7 minutes. Enjoy (m4v)!

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25 Comments

  1. Wow!

    That brings back memories of my first job 20 years ago using EE3 Designer to draw schematics and layout circuit boards. (Hope I remembered the name right).

    It’s funny that not much has really changed in PCB layout since then (apart from surface mount of course).

  2. Hello,

    I was unable to pick it up from the video, but while in Eagle after having placed a ground-pour (polygon) and clicking ratsnest do I remove the red overlay that appears and get back the original polygon which has just dashes around the outside of it? Sometimes I want to see what is going on underneath without having the polygon clouding my vision.

    Thanks,
    Bert

  3. bert, ratsnest and then click on the poly

  4. Very interesting to see this as I have no experience with manual routing. That said, I’m curious, why manual instead of auto?

  5. because autorouting rarely works, chooses improper line widths, doesnt understand proper ground planes… and even when it does work, its wasteful (space, vias) and ugly :)

  6. Kicad does things like shcematic capture like eagle if you then export your kicad netlist as a spectra file then autoroute using freeroute you can select net class widths ground planes are added after because it doen’t understand them. But it does a amazing job & the optimisation can take forever on a large design trying to make the shortest path possible. If you are a colaborator on my sites pre release you can try to route a board using it.

  7. I didn’t watch until the end, but I saw a lot of 90-degree angles in the traces. Maybe your signals aren’t at such high speeds as to worry about reflection, but I think it’s a good idea to stay in the habit of using 45-degree angles. At the very least, it looks nicer.

  8. I have done only a couple circuit boards with Eagle. Every one of them I have Autorouted. I have done a few cosmetic tweaks(moved some vias) after but have yet to have a failed board. That still goes much faster then routing the whole board by hand.

  9. ryan, its an arduino shield. data doesnt run faster than 4MHz on these things. and theres only 1 line that could even go that fast. usually for speed i put down everything as 90 degree and then at the end tweak the signal lines into 45 degrees, you have to look carefully cause it goes by fast :)

  10. daniel, no autorouter should produce faulty boards. but unless you have $10k package, they dont produce efficient and beautiful boards. autorouters simply do not know what the signals are the way the engineer does, and so designing things like ground planes, separating analog and digital ground lines, keeping clocks short, etc. is only possible by hand routing. if you watch the video you will see that parts are moved and pins are swapped to improve the routing.

    if people want to autoroute, thats fine. but i dont do it and as far as i know, none of my electrical/CAD engineer friends do it, and none of their friends/coworkers do it either, so if you want to know how i hand route, we put up a video :)

  11. Yeah thank you I did learn alot, I am going to try a ground plane in my next design.

  12. I’d love to know how to hand route. When I make a circuit in Eagle and try to start I don’t have a clue what I should be doing, so a tut would be nice!

    It will be handy to know when I finish my CNC router.

    Thanks Telly!

  13. Very interesting! You don’t often get to see the design process, just the final result. Some things I noticed:

    - You don’t seem too worried about making everything line up perfectly. Maybe I’m just obsessive but I always like everything to be neatly grid aligned and traces to be as symmetrical as possible. Actually, reading that, there is no “maybe” about it :)

    - When doing the layout you turn off all the placement and other component marks. That suggests that you don’t worry too much about placing traces near or under particular components. I suppose it makes no difference most of the time but I do tend to try and keep pads and vias away from metal case components (e.g. crystals) just in case.

    - You are extremely efficient :) What takes you 1 hour takes me three hours. I think I waste a lot of time trying to make it ‘perfect’ when in actual fact production errors are more likely to cause problems than any slightly non-optimal layout. Maybe calling it “artwork” gives me delusions of artistry ;)

    Do you etch your own boards from the designs? I don’t do my own PCBs so maybe it matters more to spend time getting it right when the turn-around is 3 weeks.

    I have run boards up to 20MHz for testing with very tight corners (two 45 degree turns close by) and have not seen any problems. I think modern components are designed well enough to negate the need to plan for high frequency signals much.

    I wish Eagle had better import features. I do artwork on my PCBs, but so far it has all been pixel stuff done with polygons on a grid copied out by hand. The ‘drawing’ tools are a bit basic and importing vectors from another app would be handy. Another issue is that there does not appear to be any way to scale polygons so you have to re-draw at different sizes.

  14. mojo, for delicate parts i usually ‘know’ i cant put signals underneath. for example, there is crystal on the bottom left. i only worry about traces when a noisy digital line is passing near an analog component or clock. in this case, its not an issue.

  15. Wow, I must have been tired when I wrote that, the sentences are missing key components that make them a sentence.

    I have just tried what you suggest, click ratsnest and then the poly, I do indeed get back the dashed line so I can move/modify it, however it is still a “solid” so seeing underneath it is an issue. The only way I have been able to go back is to close the board file and re-open it. I am really looking for a better way, as I assume it should be possible!

    Bert

  16. There, figured it out thanks to http://psas.pdx.edu/EagleCadWorkshopNotes/#index17h1. Use ratsnest to create the polygon and have it check airwires, use ripup on the outside edge of the polygon to make it clear again.

    This is going to make my life so much easier!

  17. Thanks. This is cool. But I will add that I would pay a few bucks to see the hour long version with some sort of spoken narrative about the decisions you are making. Even if it feels to you like you are rambling, we don’t care. I gain a lot from seeing folks work, but when they actually explain it, obviously there is a deeper understanding. BTW, video is also great. The Sparkfun and Instructable tutorials are great, but there is something to be said about the actual movement within Eagle that gives some insight into workflow and thought process. (Also might save hours of questions). :0D

    Thanks again

  18. I agree with myx – I’m a computer scientist turned digital electronic engineer and very thin on the practicalities of routing. I’ve produced several successful Arduino-based projects with lots of wires, and would love to see either a tutorial or (much easier for you) just a narrative during the long version of a small routing session.
    Thanks for your work and your presence on the web.

  19. Regarding reflection, there’s something really funny to me when picturing all these little electrons running full-speed down a trace and then bouncing off the wall. Kind of like those games we played as a kid in the school gym with the padded walls. :-)

    I’d also be interested in a normal-speed, narrated tutorial on using Eagle. I’m currently trying to lay out a couple of boards that I hope to make at home, but it turns out they’re more complex than I’d expected.

    Do you etch any of your own prototype boards?

  20. Auto-routing is fine until you get to very complicated board layouts in small spaces. I used to always auto-route until I got to more complicated boards, where the autorouter just seems to have no common sense.

    The board below was completely hand-routed in a fairly short amount of time, and only 4 vias to boot. Once you get the hang of manual routing it isn’t so bad

  21. http://i45.tinypic.com/dnetld.jpg

  22. Yes indeedy, I too would love the hour long version, even without narration.
    How timely this video is! Just this week I’ve been putting time into learning Eagle 5.6.0 with some effort, I also successfuly etched my first single sided PCB produced from it!
    Lots of info on the net is also on earlier versions, its pretty much the same but there are differences in some key areas which make it difficult.
    I’m still pretty fuzzy on a lot of aspects of Eagle, and fuzzy on the various signal bounce issues involved. If we had the hour long narrated or not version of this video it would be invaluable. Thank you.
    Thanks for the video as is by the way, its fascinating to watch!

  23. Are there situations where I would not want a ground plane? I’m building a stereo amp, and I’ve come across a few issues with it, but I have no idea what the source of the issues are. I am sort of hoping that adding a ground plane might fix it, but is it possible that I might make things worse? If you want to look at the PCB it’s on my website. Cheers.

  24. Mon 3/01/2010 6:22 pm. Very good! I have just spent about 5 million years discovering that you’re supposed to manual route in EagleCad and probably everywhere else! … The demo was very instructional. … Like others, I’d love a normal speed version and/or, the schematic/pcb in eagle cad form or a picture or something, so I can gaze upon it at my leisure? … Whatever, I’m grateful for you putting it up; this is the *first* time I’ve seen someone actually *using* Eagle — I mean excluding my pitiful gropings.

    j.g. owen * * * * * * * * *
    email: owen_bda4@yahoo.com
    web: http://owenlabs.org
    * * * * * * * * * * * * * *

  25. Thanks so much for putting that up! I’ve just started learning Eagle, using the Sparkfun tutorials, and they say "just click on autoroute". I tried that, and it did route, but it was … unsatisfying. Inelegant. Why are all these vias here? If this trace was just run sanely, these others would go much more neatly. After watching your video, I ripped it all up and gave it a go. And (as I’m sure you already know), it’s kind of fun. Sort of Zen, just get in there and see how things should go. I’ve redone almost all of it a few times now, but I’m getting a nice layout I can be proud of (a simple shield). So, again, thanks!

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